An Israeli soldier and at least 23 Palestinians have been killed since Israeli military launched a large-scale ground campaign in Gaza, according to Palestinian officials.

The offensive was aimed at destroying the weapons arsenal, infrastructure and underground tunnels used by Hamas, Israeli officials said.

"The prime minister and defence minister have instructed the Israel Defence Forces (IDF) to begin a ground operation tonight in order to hit the terror tunnels from Gaza into Israel," said a statement from Benjamin Netanyahu's office.

By daylight IDF reported it had "neutralised 14 terrorists, destroyed 20 rocket launchers, carried out nine strikes on tunnels and hit a total of 103 terror targets".

Smoke billows in Gaza after an air strike on Friday

Israel confirmed 20-year-old Sgt Eitan Barak had been "killed fighting Hamas terrorists". The country's media is investigating the possibility he was a victim of so-called friendly fire.

Israel stepped up its ground offensive in Gaza early on Friday, pounding targets with artillery fire and using tanks and infantry to battle Hamas fighters.

She said: "The power has gone out over most of Gaza so we can't see very much, but what we can hear is terrifying.

"We have heard the sounds of constant bombardment coming from the naval ships for the past few hours. We have also seen flares lobbed over essentially to light up targets in Gaza and they were then shelled by the naval ships.

"We have also been hearing airstrikes and reports of many casualties going to the various hospitals.

Video:Israeli Assault On Gaza Begins

"The power outage is causing havoc."

Gaza health officials said the 23 killed in the operation included a three-month-old boy who died after a shell hit his family's Bedouin tent in southern Gaza.

The operation comes after 10 days of intense fighting between Israel and the Islamic militant Hamas.

Video:Israeli Assault 'Has Limited Goals'

It is the first major Israeli ground offensive in Gaza in just over five years.

The army has confirmed that a draft of 18,000 more reserve soldiers has been authorised by the government.

Mr Netanyahu's chief spokesman Mark Regev told Sky News the decision to launch the offensive had not been taken "lightly" but that action needed to be taken to "protect our citizens".

Video:'Hamas Torpedoed Ceasefire Chance'

He said the chance of a ceasefire is now very unlikely: "This operation is only happening because Hamas rejected the ceasefire proposal supported by Egypt, a proposal supported by the United Nations."

Hamas chief Khaled Meshaal said the operation was destined to fail, in remarks to AFP in the Qatari capital.

"What the occupier Israel failed to achieve through its air and sea raids, it will not be able to achieve with a ground offensive. It is bound to fail," Mr Meshaal said from his exile in Doha.

The ground campaign followed a brief truce earlier on Thursday in which Israel held fire to allow Gazans to stock up on food and other necessities after being largely holed up at home since the conflict began last month.

Video:Video Of Hamas Tunnel Weapons Haul

1/19

Gallery: Gaza-Israel Conflict Flares Up

A Palestinian woman cries inside her damaged house, which police said was targeted in an Israeli airstrike, in Gaza City. At least 224 Palestinians and an Israeli have been killed in 10 days of cross-border fighting.